Escapement



J. BOURQUIN ESCAPEMENT May 15, 1962 Filed April 6, 1959 I I I Jun :LNVENTQR zwtv PMQ Y: WM,

rates This invention relates to parts of clock and watch movements which have surfaces which are in sliding contact, and it relates particularly to parts of the escapement mechanism of clock and watch movements.

Such parts are at present usually made of brass and sometimes of steel. When such parts are made in the conventional manner, difficulties frequently arise, because the unsatisfactoryproperties of the materials as regards their ability to slide on one another cause friction between the surfaces in sliding contact to increase, or because the surfaces which are in sliding contact corrode or pit and thus adversely affect the running of the clock or watch.

According to the disclosure in a copending application Serial No. 711,214 in the name of F. Straumann and H. Bourquin, and relating to self-winding watches, the properties of the coacting surfaces of barrel and mainspring which cause them to slide on each other, which parts, as is known, constitute a slip coupling, can be improved by making the barrel of anodically oxidized aluminum. The surface layer thus produced has better frictional properties and corrosion or pitting of the sliding surfaces does not occur.

atent fiicc It is also conventional in watches and clock mechanisms to use bearings of anodized aluminum in combination with steel shafts or pointed steel bearings.

The present invention however, relates neither to bearings nor to spring barrels, but to escapement mechanisms.

It is an object of the present invention not only to reduce the inertia of escapement parts in clock and watch movements of all kinds, such as for instance the inertia of the escape wheel, pallet and anchor, but also to improve the mechanical and physical properties of these parts of clocks and watches by making these parts of an anodically oxidizable aluminum or an anodically oxidizable aluminum alloy.

11: is a further object of the present invention to provide an escapement mechanism in which the large moving parts are of an anodically oxidized aluminum or aluminum al- 10y, and the parts bearing on said large moving parts are of a rustproof alloy taken from the group consisting of iron-cobalt, iron-nickel-chromium, and iron-nickel-cobaltchromium alloys, which alloys have been heat treated to have a tensile strength of at least 180 kg./mm. and a Vickers hardness of above 650 kg./mm.

An advantage of this combination of friction surfaces, one of an anodically oxidized aluminum or aluminum alloy and the other of a rustproof alloy which has a tensile strength of at least 180 kg/mm. and a Vickers hardness of above 650 kg./mm. is that it exhibits the best frictional properties and in such a combination no corrosion occurs.

Another advantage of having parts consisting of aluminum or an aluminum alloy is that the weight is less than when the parts consist of heavy metal alloys, so that their inertia is lower, and they therefore require less energy to keep them in motion. Moreover, due to the lower weight, bearing pressures and friction are also reduced.

Still another advantage is that parts of clocks and watches made, according to the invention of aluminum alloys are largely corrosion resistant and non-magnetic and they can also be easily machined.

Moreover, it is known in the art that an important dis- 3,034,286 Patented May 15, 1962 advantage of escapement mechanisms having an escape wheel of brass and anchor pins of steel is that after a certain time a constantly increasing layer of black paste forms on the anchor pins, which paste consists of old oil and metal particles formed by abrasion and dust, and which impairs the accurate functioning of the watch. With the combination of parts according to the present invention the anodically oxidized parts are rustproof, and

substantially fewer metal abrasion particles accumulate so.

that the accurate operation of the watch continues for a longer period of time than heretofore. Any oil which might be present would thicken the dust. Extensive experiments have shown that it is possible for an escapement mechanism to operate without oil lubrication. Therefore, in the mechanism according to the invention the parts can operate either without any lubrication, or an oil free lubrication system can be used such as a system in which the parts are coated with a plastic layer less than one micron in thickness containing carbon monofiuorid as a lubricant. Alternatively, the layer can be a film of soap or a detergent. A somewhat difierent lubrication system which is possible is one in which the parts are coated with a tightly adhering, non-sticky coating of a plastic containing a high pressure lubricant. This may for example be a salt of stearic acid. A still further possibility is a lubrication system which is created by causing the surface of the parts which are to be in sliding frictional contact to adsorb a vapor which will act as a lubricant by surrounding them with the said vapor.

The fact that the escapement mechanism according to the invention operates without oil, and may even operate without any lubrication means at all, is an unusually im portant advance as regards escapements.

The attached drawings show an embodiment of present invention. In the drawings:

FIG. 1 is a top plan view of an escapement mechanism of a watch; and

FIG. 2 is a section on line IIII of FIG. 1, but on an enlarged scale.

The anchor 1 is pivoted, for example on a frame (not shown) on a pin 2. It is provided with two anchor pins 3 and 4 which retard the escape wheel 5 and release it to the ' transmit the impulses from the escape wheel through the anchor to the balance wheel. The escape wheel 5 is mounted on shaft 6. A balance wheel shaft 7 is also provided. On one end of balance wheel shaft 7 is a roller 8 to which one end of the spiral spring 9 is fastened. The other end of spiral spring 9 is connected to the working plate (not shown in the drawing) by the small block 10. Below the roller 8 on the balance shaft 7 is mounted the balance wheel 11, one part of which is broken away in the drawing. Below the balance wheel is located the lifting cylinder 12 which is formed from a single body together with the safety cylinder 13. The lifting cylinder 12 carries the lifting pin 14-, which fits into the notch 15 of the fork 16 forming one part of the anchor 1. To the fork 16 is rivetted the safety knife 17 which, together with the safety roller 13 prevents recoil of the anchor.

This construction of such an anchor escapement mechanism is known in the art, so that a detailed description of the operation of the mechanism would be superfluous. It is sufficient for the present purpose to state that in said anchor escapement mechanism on the one hand the escape wheel 5 slidingly engages the pins 3 and 4, and on the other hand the fork 16 slidingly engages the lifting pin 14.

When manufacturing such a mechanism according to the present invention, the escape wheel 5 and the anchor 1 are made from aluminum or an aluminum alloy and the finished parts anodically oxidized, so that they have an anodically oxidized surface layer. The pins 3 and 4 as well as the lifting pin 14 are made of a rustproof alloy.

Aluminum alloys suitable for the escapement wheel and the pallet fork according to the invention include hardenable alloys such as those of the compositions given in Table A.

. 4 temperature of 420 C. for the Vickers hardness increases until at least 650 kg/mmf The desired form of the work piece can be achieved by turning, cutting or Table A grinding. a If there is used a sheet metal asstarting material, it can I be heat treated at 1050 C., quenched in water, and cold I H In rolled to get a reduction of cross section of 90%, the desired parts can be worked out, for instance by punching, Perm Pmem and annealed during 2 hours at 450 C.

3 5 5 -5% Using one of the alloys 6-11, the material is heat treated 2: 1 5 L preferably at a temperature of 1150 C. in air or in a pro- 0 gig tective atmosphere and quenched in water. After cold ""gfgl; deformation to receive a reduction of cross section of Rest Rest Rest 80-95% the parts will be worked out and annealed during 4 hours at a temperature of 480 C. for reaching a Vickers For improving their mechanical strength these alloys may hardness of about 700 kg/mmF. advantageously be subjected to a suitable heat treatment. This application is a continuation-in-part of United For instance, the strength of alloy I can be improved by States application Serial No. 731,096, filed April 28, 1958, quenching the alloy from a temperature range of 530 C. now abandoned. to 550 C. down to about room temperature and age I claim: harding it at a temperature of 155 C. to 160 C. for 1. In a watch mechanism, the combination of an oscilabout 4 hours. The strength of alloy II can be improved latingly movable part of an anodically oxidized metal by quenching it from the temperature range of 505 C. to taken from the group consisting of aluminum and harden- 515 C. down to about room temperature and aging it at able aluminum alloys, and a further part with which said room temperature for about 100 hours. The strength of movable part is in sliding frictional contact for at least alloy III can be improved by heating the said alloy within part of the oscillatory movement of said movable part, said the temperature range of 400 C. to 440 C. for about further part being of a heat treated and cold Worked rust- 5 hours, followedwith or without a quenching operation proof alloy having a tensile strength of at least 180 to about room temperature-by heating the alloy for 4 to kg./mm. and a Vickers hardness of over 650 kg./mm. 8 hours at between 250 C. and 340 C. said alloy being an alloy taken from the group of precipi- As a rustproof material for the pins which have surfaces tation hardenable 42-48% iron27-33% cobalt alloys in sliding contact with the anodically oxidized aluminum, having minor percentages of other metals therein, precipiamong others, the alloys of Table B can be used. tation hardenable 317% iron14.5-26.5% nickel- Table B V Rest Rest Rest Rest 15:1:1. 5 16ml. 6 Rest 215:2 93:1 9. :1 9. vii 7. 5:111 1&1. 6 Rest 0.25:0.1 0.s=|=0.2 0.1i0.02 0.1:;002 (10710.02 0. 15:0. 02 0. 04:1;0. 01 0 l5:l:0. 02 17=1=1.7 18:l:l.8 1s.5a=1.9 16.5:|:L7 20:1:2 16in; 0. 5:1:0.2 0. 4:l:0.2 0.4:e0.2 1. 23:0.3 1. 25:03 2:1:0. 5 1.1=i=0.2 1.13:0.3 1.2=|=0.3 7=|=1 e. 85:1.0

tlfif dfibfi' 0. Will. 01 1. 83:0. 5

From each of these alloys can be manufactured pins 25-65% cobalt8-22% chromium alloys having minor which, after a suitable heat treatment, have a tensile percentages of other metals therein, and precipitation strength of at least 180' kg./mm. and a Vickers hardness hardenable 58-62% nickel-l4-18% iron-and 1.3.5- of above 65 0 kg./mrn. 16.5% chromium alloys having minor percentages of other By cold-forming these alloys in an amount which remetals therein. duces the cross section of the material being formed up to 2. In a watch mechanism, the combination of an oscil- 90% and more, ultimate stress values of above 180 latingly movable part of an anodically oxidized metal kg./mm. can also be obtained which are favorable for 5 taken from the group consisting of aluminum and quenchsuch a pin, as well as coefficients of hardness of above able and age hardenable aluminum-magnesium-manganese 650 kg./mm. alloys, and a further part with which said movable part The material has to be treated according to the type of is in sliding frictionable contact for at least part of the alloy so that the finished parts reach the necessary tensile oscillatory movement of said movable part, said further strength and the desired Vickers hardness. 60 part being of a heat treated and cold worked rustproof :For the manufacturing of parts from the alloy No. 1 alloy having a tensile strength of at least 180 kg./rnm. one uses a piece of said material which is to be treated at and a Vickers hardness of over 650 kg/mrn. said alloy 900 C. during 5 hours and then cooled down slowly. being an alloy taken from the group of precipitation hard- Afterwards it will be heat treated during 15 minutes at a enable 42-48% iro n-27-33% cobalt alloys having minor temperature of 1250 C. zmd quenched in a lead bath of percentages of other metals therein, precipitation harden- 600 C. After cooling inair there will be given the deable 31-17% iron-14.5-26.5% nickel-25-65% cobaltsired form to it by metal cutting. For reaching a Vickers 23-22% chromium alloys having minor percentages of hardness of about 1000 kg./mm. the parts are to be other metals therein, and precipitation hardenable 58-62% annealed during 20 minutes at a temperature of 600 C. nickel14-l8% ironand 13.5-16.5 chromium alloys To manufacture pins and the like of one of the alloys having minor percentages of other metals therein. 2-5 one takes as starting material a Wire. After heat 3. In an escapement mechanism fora watch, the comtreating it during 15 minutes at a temperature of 1000 C. bination of an anchor-of an anodically oxidized metal the wire is quenched in water and cold-drawn until the taken from the group consisting of aluminum and hardenreduction of cross section is about 90%. Then, the maable aluminum alloys, and a lifting pin with which said terial is straightened and annealed during 4 hours at a anchor is insliding frictional contact for at least part of the oscillatory movement of said anchor, said lifting pin being of a heat treated and cold worked rustproof alloy having a tensile strength of at least 180 kg./mrn. and a Vickers hardness of over 650 kg./mm. said alloy being an alloy taken from the group of precipitation hardenable 42-48% iron-27-33% cobalt alloys having minor percentages of other metals therein, precipitation hardenable 3-17% iron-14.5-26.5% nickel-25-65% cobalt 8-22% chromium alloys having minor percentages of other metals therein, and precipitation hardenable 58-62% nickel-l4-18% ironl3.5-l6.5% chromium alloys having minor percentages of other metals therein.

4. In an cscapement mechanism for a Watch, the combination of an escape wheel of an anodically oxidized metal taken from the group consisting of aluminum and hardenable aluminum alloys, and a plurality of anchor pins with which said escape Wheel is in sliding frictional contact for at least part of the oscillatory movement of said escape wheel, said anchor pins being of a heat treated and cold Worked rust-proof alloy having a tensile strength of at least 180 kg./mm. and a Vickers hardness of over 650 kg./mrn. said alloy being an alloy taken from the group of precipitation hardenable 42-48% iron-27-33% cobalt alloys having minor percentages of other metals therein, precipitation hardenable 3-17- iron-l4.5- 26.5% nickel-25-65% cobalt-8-22% chromium alloys having minor percentages of other metals therein, and precipitation hardenable 58-62% nickell4l8% ironand 13.5-16.5% chromium alloys having minor percentages of other metals therein.

5. The combination as claimed in claim 1 in which said anodically oxidized metal has the composition Mg 0.5%-1% Mn O.2%-l% Si 0.5%-l.5% Al Rest 6. The combination as claimed in claim 1 in which said anodically oxidized metal has the composition Cu 3.5%-5% Mg 0.2%1.5% Mn 0.2%-1.5% Si 0l% Al Rest 7. The combination as claimed in claim 1 in which said anodically oxidized metal has the composition Cr O.1%l% Cu l%-2.5% Mg 2%3% Mn 0.2%-1% Z11 5.5%-7% A1 Rest References Cited in the file of this patent I UNITED STATES PATENTS Ohlson June 4, 1907 

